This invention is related to a 3D measurement system that uses laser-light and estimates depth information of an object by applying a triangulation method; among these systems, this invention is especially related to a 3D measurement system that consists of a single camera to acquire accurate depth information. This invention also relates to a 3D measurement method using the 3D measurement system.
To acquire a 3D shape of the object, an active stereo method based on the triangulation method is well known (pattern projection method and point projection method). These systems consist of light sources, such as laser-lights or halogen lights, and image capturing devices, such as cameras or CCD (Charge-coupled Device) cameras. 3D shape estimation is conducted by a triangulation method of these devices. Therefore, a precise relationship between the light source and the camera should be precalibrated, and thus, the whole system is prone to become large and complicated.
If we can make the calibration process of the light source and the camera easier, an active 3D acquisition system becomes simpler. Based on such an idea, a method was proposed that achieves easy calibration of the light source and the camera by attaching markers on the light source itself and capturing it with a single camera (Masahiro Takatsuka, Geoff A. W. West, Svetha Venkatesh, and Terry M. Caelli. “Low-cost interactive active monocular range finder”. In Proceeding of Computer Vision and Pattern Recognition, volume 1, pages 444-449, 1999.).